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Zhu Y, Li Q. Multifaceted roles of PDCD6 both within and outside the cell. J Cell Physiol 2024; 239:e31235. [PMID: 38436472 DOI: 10.1002/jcp.31235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 02/15/2024] [Accepted: 02/20/2024] [Indexed: 03/05/2024]
Abstract
Programmed cell death protein 6 (PDCD6) is an evolutionarily conserved Ca2+-binding protein. PDCD6 is involved in regulating multifaceted and pleiotropic cellular processes in different cellular compartments. For instance, nuclear PDCD6 regulates apoptosis and alternative splicing. PDCD6 is required for coat protein complex II-dependent endoplasmic reticulum-to-Golgi apparatus vesicular transport in the cytoplasm. Recent advances suggest that cytoplasmic PDCD6 is involved in the regulation of cytoskeletal dynamics and innate immune responses. Additionally, membranous PDCD6 participates in membrane repair through endosomal sorting complex required for transport complex-dependent membrane budding. Interestingly, extracellular vesicles are rich in PDCD6. Moreover, abnormal expression of PDCD6 is closely associated with many diseases, especially cancer. PDCD6 is therefore a multifaceted but pivotal protein in vivo. To gain a more comprehensive understanding of PDCD6 functions and to focus and stimulate PDCD6 research, this review summarizes key developments in its role in different subcellular compartments, processes, and pathologies.
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Affiliation(s)
- Yigao Zhu
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Qingchao Li
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
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2
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Yang Y, Wang M, Zhang YY, Zhao SZ, Gu S. The endosomal sorting complex required for transport repairs the membrane to delay cell death. Front Oncol 2022; 12:1007446. [PMID: 36330465 PMCID: PMC9622947 DOI: 10.3389/fonc.2022.1007446] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 09/20/2022] [Indexed: 08/15/2023] Open
Abstract
The endosomal sorting complex required for transport (ESCRT) machinery plays a key role in the repair of damaged plasma membranes with puncta form and removes pores from the plasma membrane in regulated cell death, apoptosis, necroptosis, pyroptosis, ferroptosis, and autophagy. ESCRT-I overexpression and ESCRT-III-associated charged multivesicular body protein (CHMP) 4B participate in apoptosis, and the ESCRT-1 protein TSG 101 maintains low levels of ALIX and ALG-2 and prevents predisposition to apoptosis. The ESCRT-III components CHMP2A and CHMP4B are recruited to broken membrane bubble sites with the requirement of extracellular Ca2+, remove membrane vesicles from cells, and delay the time required for active MLKL to mediate necroptosis, thus preserving cell survival. CHMP4B disturbed pyroptosis by recruiting around the plasma membrane neck to remove the GSDMD pores and preserve plasma membrane integrity depending on Ca2+ influx. The accumulation of the ESCRT-III subunits CHMP5 and CHMP6 in the plasma membrane is increased by the classical ferroptosis activators erastin-1 and ras-selective lethal small molecule 3 (RSL3) upon cytosolic calcium influx and repairs the ferroptotic plasma membrane. ESCRT-III- and VPS4-induced macroautophagy, ESCRT-0-initiated microautophagy. ESCRT-I, ESCRT-II, ESCRT-III, ALIX, and VPS4A are recruited to damaged lysosomes and precede lysophagy, indicating that ESCRT is a potential target to overcome drug resistance during tumor therapy.
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Affiliation(s)
- Ye Yang
- Obstetrics and Gynecology Department, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Min Wang
- General Surgery Department, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ying-Ying Zhang
- Respiratory and Critical Care Medicine Department, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shu-Zhi Zhao
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People’s Hospital), Shanghai Jiao Tong University School of Medicine, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Song Gu
- Trauma Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Qiu X, Campos Y, van de Vlekkert D, Gomero E, Tanwar A, Kalathur R, Weesner JA, Bongiovanni A, Demmers J, d'Azzo A. Distinct functions of dimeric and monomeric scaffold protein Alix in regulating F-actin assembly and loading of exosomal cargo. J Biol Chem 2022; 298:102425. [PMID: 36030822 PMCID: PMC9531180 DOI: 10.1016/j.jbc.2022.102425] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/11/2022] [Accepted: 08/12/2022] [Indexed: 11/17/2022] Open
Abstract
Alix is a ubiquitously expressed scaffold protein that participates in numerous cellular processes related to the remodeling/repair of membranes and the actin cytoskeleton. Alix exists in monomeric and dimeric/multimeric configurations, but how dimer formation occurs and what role the dimer has in Alix-mediated processes are still largely elusive. Here, we reveal a mechanism for Alix homodimerization mediated by disulfide bonds under physiological conditions, and demonstrate that the Alix dimer is enriched in exosomes and F-actin cytoskeleton subcellular fractions. Proteomic analysis of exosomes derived from Alix-/- primary cells underlined the indispensable role of Alix in loading syntenin into exosomes, thereby regulating the cellular levels of this protein. Using a set of deletion mutants, we define the function of Alix Bro1 domain, which is solely required for its exosomal localization, and that of the V domain, which is needed for recruiting syntenin into exosomes. We reveal an essential role for Cys814 within the disordered proline rich domain (PRD) for Alix dimerization. By mutating this residue, we show that Alix remains exclusively monomeric and, in this configuration, is effective in loading syntenin into exosomes. In contrast, loss of dimerization affects the ability of Alix to associate with F-actin, thereby compromising Alix-mediated cytoskeleton remodeling. We propose that dimeric and monomeric forms of Alix selectively execute two of the protein's main functions: exosomal cargo loading and cytoskeleton remodeling.
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Affiliation(s)
- Xiaohui Qiu
- Department of Genetics, St Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis Tennessee 38105, USA
| | - Yvan Campos
- Department of Genetics, St Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis Tennessee 38105, USA
| | - Diantha van de Vlekkert
- Department of Genetics, St Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis Tennessee 38105, USA
| | - Elida Gomero
- Department of Genetics, St Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis Tennessee 38105, USA
| | - Ajay Tanwar
- Department of Structural Biology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Ravi Kalathur
- Department of Structural Biology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Jason A Weesner
- Department of Genetics, St Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis Tennessee 38105, USA; Department of Anatomy and Neurobiology, College of Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Antonella Bongiovanni
- Institute of Biomedical Research and Innovation (IRIB), National Research Council (CNR) of Italy, Palermo, Italy
| | - Jeroen Demmers
- Proteomics Center, Erasmus Medical Center, Wytemaweg 80, 3015 CN, Rotterdam, The Netherlands
| | - Alessandra d'Azzo
- Department of Genetics, St Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis Tennessee 38105, USA.
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Lokapally A, Neuhaus H, Herfurth J, Hollemann T. Interplay of TRIM2 E3 Ubiquitin Ligase and ALIX/ESCRT Complex: Control of Developmental Plasticity During Early Neurogenesis. Cells 2020; 9:cells9071734. [PMID: 32698497 PMCID: PMC7409263 DOI: 10.3390/cells9071734] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/13/2020] [Accepted: 07/15/2020] [Indexed: 01/26/2023] Open
Abstract
Tripartite motif 2 (TRIM2) drives neurite outgrowth and polarization, is involved in axon specification, and confers neuroprotective functions during rapid ischemia. The mechanisms controlling neuronal cell fate determination and differentiation are fundamental for neural development. Here, we show that in Xenopus, trim2 knockdown affects primary neurogenesis and neural progenitor cell survival. Embryos also suffer from severe craniofacial malformation, a reduction in brain volume, and the loss of motor sensory function. Using a high-throughput LC-MS/MS approach with GST-Trim2 as bait, we pulled down ALG-2 interacting protein X (Alix) from Xenopus embryonic lysates. We demonstrate that the expression of trim2/TRIM2 and alix/ALIX overlap during larval development and on a cellular level in cell culture. Interestingly, trim2 morphants showed a clustering and apoptosis of neural progenitors, which are phenotypic hallmarks that are also observed in Alix KO mice. Therefore, we propose that the interaction of Alix and Trim2 plays a key role in the determination and differentiation of neural progenitors via the modulation of cell proliferation/apoptosis during neurogenesis.
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Affiliation(s)
- Ashwin Lokapally
- Institute for Physiological Chemistry, Martin-Luther University Halle-Wittenberg, Hollystrasse 1, 06114 Halle, Germany; (A.L.); (H.N.); (J.H.)
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
| | - Herbert Neuhaus
- Institute for Physiological Chemistry, Martin-Luther University Halle-Wittenberg, Hollystrasse 1, 06114 Halle, Germany; (A.L.); (H.N.); (J.H.)
| | - Juliane Herfurth
- Institute for Physiological Chemistry, Martin-Luther University Halle-Wittenberg, Hollystrasse 1, 06114 Halle, Germany; (A.L.); (H.N.); (J.H.)
| | - Thomas Hollemann
- Institute for Physiological Chemistry, Martin-Luther University Halle-Wittenberg, Hollystrasse 1, 06114 Halle, Germany; (A.L.); (H.N.); (J.H.)
- Correspondence:
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Khan A, Alaamery M, Massadeh S, Obaid A, Kashgari AA, Walsh CA, Eyaid W. PDCD6IP, encoding a regulator of the ESCRT complex, is mutated in microcephaly. Clin Genet 2020; 98:80-85. [PMID: 32286682 DOI: 10.1111/cge.13756] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 03/10/2020] [Accepted: 03/12/2020] [Indexed: 12/14/2022]
Abstract
Primary microcephaly (PM) is a highly heterogeneous neurodevelopmental disorder with many contributing risk genes and loci identified to date. We report a consanguineous family with PM, intellectual disability and short stature. Using whole exome sequencing, we identified a homozygous frameshift variant in programmed cell death 6 interacting protein (PDCD6IP, c.154_158dup; p.Val54Profs*18). This gene, PDCD6IP, plays an important role in the endosomal sorting complexes required for transport (ESCRT) pathway in the abscission stage of cytokinesis and apoptosis, and is required for normal brain development in mice. The clinical features observed in our patient were similar to the phenotypes observed in mouse and zebrafish models of PDCD6IP mutations in previous studies. This study provides evidence that clinical manifestations of PDCD6IP mutations as seen in our patients with PM and ID may be a novel cause for neurodevelopmental disorders.
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Affiliation(s)
- Amjad Khan
- Developmental Medicine Department, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia.,Laboratoire d'ImmunoRhumatologie Moléculaire, Plateforme GENOMAX, INSERM UMR_S 1109, Faculté de Médecine, Fédération Hospitalo-Universitaire OMICARE, Fédération de Médecine Translationnelle de Strasbourg (FMTS), LabEx TRANSPLANTEX, Université de Strasbourg, Strasbourg, France.,Service d'Immunologie Biologique, Plateau Technique de Biologie, Pôle de Biologie, Nouvel Hôpital Civil, Hôpitaux Universitaires de Strasbourg, 1 Place de l'Hôpital, Strasbourg, France
| | - Manal Alaamery
- Developmental Medicine Department, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia
| | - Salam Massadeh
- Developmental Medicine Department, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia
| | - Abdulrahman Obaid
- Genetics Division, Department of Pediatrics, King Abdullah International Medical Research Centre (KAIMRC), King Saud bin Abdulaziz University for Health Science, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (MNGHA), Riyadh, Saudi Arabia
| | - Amna A Kashgari
- King Abdullah Specialized Children's Hospital (KASCH), Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
| | - Christopher A Walsh
- Division of Genetics and Genomics and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts.,Department of Neurology, Harvard Medical School, Boston, Massachusetts
| | - Wafaa Eyaid
- Developmental Medicine Department, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia.,Genetics Division, Department of Pediatrics, King Abdullah International Medical Research Centre (KAIMRC), King Saud bin Abdulaziz University for Health Science, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (MNGHA), Riyadh, Saudi Arabia.,King Abdullah Specialized Children's Hospital (KASCH), Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
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Arkadir D, Lossos A, Rahat D, Abu Snineh M, Schueler-Furman O, Nitschke S, Minassian BA, Sadaka Y, Lerer I, Tabach Y, Meiner V. MYORG is associated with recessive primary familial brain calcification. Ann Clin Transl Neurol 2018; 6:106-113. [PMID: 30656188 PMCID: PMC6331209 DOI: 10.1002/acn3.684] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 09/23/2018] [Accepted: 10/11/2018] [Indexed: 12/12/2022] Open
Abstract
Objective To investigate the genetic basis of the recessive form of primary familial brain calcification and study pathways linking a novel gene with known dominant genes that cause the disease. Methods Whole exome sequencing and Sanger‐based segregation analysis were used to identify possible disease causing mutations. Mutation pathogenicity was validated by structural protein modeling. Functional associations between the candidate gene, MYORG, and genes previously implicated in the disease were examined through phylogenetic profiling. Results We studied nine affected individuals from two unrelated families of Middle Eastern origin. The median age of symptom onset was 29.5 years (range 21–57 years) and dysarthria was the most common presenting symptom. We identified in the MYORG gene, a homozygous c.1233delC mutation in one family and c.1060_1062delGAC mutation in another. The first mutation results in protein truncation and the second in deletion of a highly conserved aspartic acid that is likely to disrupt binding of the protein with its substrate. Phylogenetic profiling analysis of the MYORG protein sequence suggests co‐evolution with a number of calcium channels as well as other proteins related to regulation of anion transmembrane transport (False Discovery Rate, FDR < 10−8) and with PDCD6IP, a protein interacting with PDGFRβ which is known to be involved in the disease. Interpretation MYORG mutations are linked to a recessive form of primary familial brain calcification. This association was recently described in patients of Chinese ancestry. We suggest the possibility that MYORG mutations lead to calcification in a PDGFRβ‐related pathway.
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Affiliation(s)
- David Arkadir
- Department of Neurology Agnes Ginges Center for Human Neurogenetics Hadassah Medical Center Jerusalem Israel
| | - Alexander Lossos
- Department of Neurology Agnes Ginges Center for Human Neurogenetics Hadassah Medical Center Jerusalem Israel
| | - Dolev Rahat
- The Institute for Medical Research Israel-Canada (IMRIC) the Hebrew University Jerusalem Israel
| | - Muneer Abu Snineh
- Department of Neurology Agnes Ginges Center for Human Neurogenetics Hadassah Medical Center Jerusalem Israel
| | - Ora Schueler-Furman
- The Institute for Medical Research Israel-Canada (IMRIC) the Hebrew University Jerusalem Israel
| | - Silvia Nitschke
- Program in Genetics and Genome Biology The Hospital for Sick Children Research Institute Toronto Ontario Canada
| | - Berge A Minassian
- Program in Genetics and Genome Biology The Hospital for Sick Children Research Institute Toronto Ontario Canada.,Division of Neurology Department of Pediatrics University of Texas Southwestern Dallas Texas
| | - Yair Sadaka
- Neuro-Developmental Research Centre Beer Sheba Mental Health Centre Ministry of Health BeerSheba Israel
| | - Israela Lerer
- Department of Genetics and Metabolic Diseases Center for Clinical Genetics Hadassah Medical Center Jerusalem Israel
| | - Yuval Tabach
- The Institute for Medical Research Israel-Canada (IMRIC) the Hebrew University Jerusalem Israel
| | - Vardiella Meiner
- Department of Genetics and Metabolic Diseases Center for Clinical Genetics Hadassah Medical Center Jerusalem Israel
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7
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Nixon RA. Amyloid precursor protein and endosomal-lysosomal dysfunction in Alzheimer's disease: inseparable partners in a multifactorial disease. FASEB J 2017; 31:2729-2743. [PMID: 28663518 DOI: 10.1096/fj.201700359] [Citation(s) in RCA: 202] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 04/21/2017] [Indexed: 12/15/2022]
Abstract
Abnormalities of the endosomal-lysosomal network (ELN) are a signature feature of Alzheimer's disease (AD). These include the earliest known cytopathology that is specific to AD and that affects endosomes and induces the progressive failure of lysosomes, each of which are directly linked by distinct mechanisms to neurodegeneration. The origins of ELN dysfunction and β-amyloidogenesis closely overlap, which reflects their common genetic basis, the established early involvement of endosomes and lysosomes in amyloid precursor protein (APP) processing and clearance, and the pathologic effect of certain APP metabolites on ELN functions. Genes that promote β-amyloidogenesis in AD (APP, PSEN1/2, and APOE4) have primary effects on ELN function. The importance of primary ELN dysfunction to pathogenesis is underscored by the mutations in more than 35 ELN-related genes that, thus far, are known to cause familial neurodegenerative diseases even though different pathogenic proteins may be involved. In this article, I discuss growing evidence that implicates AD gene-driven ELN disruptions as not only the antecedent pathobiology that underlies β-amyloidogenesis but also as the essential partner with APP and its metabolites that drive the development of AD, including tauopathy, synaptic dysfunction, and neurodegeneration. The striking amelioration of diverse deficits in animal AD models by remediating ELN dysfunction further supports a need to integrate APP and ELN relationships, including the role of amyloid-β, into a broader conceptual framework of how AD arises, progresses, and may be effectively therapeutically targeted.-Nixon, R. A. Amyloid precursor protein and endosomal-lysosomal dysfunction in Alzheimer's disease: inseparable partners in a multifactorial disease.
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Affiliation(s)
- Ralph A Nixon
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, New York, USA; .,Department of Psychiatry and Department of Cell Biology, New York University Langone Medical Center, New York, New York, USA
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8
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Kaul Z, Chakrabarti O. Tumor susceptibility gene 101 regulates predisposition to apoptosis via ESCRT machinery accessory proteins. Mol Biol Cell 2017; 28:2106-2122. [PMID: 28539405 PMCID: PMC5509423 DOI: 10.1091/mbc.e16-12-0855] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 05/11/2017] [Accepted: 05/16/2017] [Indexed: 12/21/2022] Open
Abstract
The ESCRT-I protein TSG101 can mitigate endoplasmic reticulum stress–mediated apoptosis involving caspase 4/12 caused by MGRN1 depletion, probably contributing to neurodegeneration. TSG101 associates with ALIX to prevent predisposition to apoptosis, whereas ALIX–ALG-2 interaction favors a cell death phenotype. ESCRT proteins are implicated in myriad cellular processes, including endosome formation, fusion of autophagosomes/amphisomes with lysosomes, and apoptosis. The role played by these proteins in either facilitating or protecting against apoptosis is unclear. In this study, while trying to understand how deficiency of Mahogunin RING finger 1 (MGRN1) affects cell viability, we uncovered a novel role for its interactor, the ESCRT-I protein TSG101: it directly participates in mitigating ER stress–mediated apoptosis. The association of TSG101 with ALIX prevents predisposition to apoptosis, whereas ALIX–ALG-2 interaction favors a death phenotype. Altered Ca2+ homeostasis in cells and a simultaneous increase in the protein levels of ALIX and ALG-2 are required to elicit apoptosis by activating ER stress–associated caspase 4/12. We further demonstrate that in the presence of membrane-associated, disease-causing prion protein CtmPrP, increased ALIX and ALG-2 levels are detected along with ER stress markers and associated caspases in transgenic brain lysates and cells. These effects were rescued by overexpression of TSG101. This is significant because MGRN1 deficiency is closely associated with neurodegeneration and prenatal and neonatal mortality, which could be due to excess cell death in selected brain regions or myocardial apoptosis during embryonic development.
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Affiliation(s)
- Zenia Kaul
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata 700064, India
| | - Oishee Chakrabarti
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata 700064, India
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Adair BD, Altintas MM, Möller CC, Arnaout MA, Reiser J. Structure of the kidney slit diaphragm adapter protein CD2-associated protein as determined with electron microscopy. J Am Soc Nephrol 2014; 25:1465-73. [PMID: 24511139 DOI: 10.1681/asn.2013090949] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
CD2-associated protein (CD2AP) is a multidomain scaffolding protein that has a critical role in renal function. CD2AP is expressed in glomerular podocytes at the slit diaphragm, a modified adherens junction that comprises the protein filtration barrier of the kidney, and interacts with a number of protein ligands involved in cytoskeletal remodeling, membrane trafficking, cell motility, and cell survival. The structure of CD2AP is unknown. We used electron microscopy and single particle image analysis to determine the three-dimensional structure of recombinant full-length CD2AP and found that the protein is a tetramer in solution. Image reconstruction of negatively stained protein particles generated a structure at 21 Å resolution. The protein assumed a roughly spherical, very loosely packed structure. Analysis of the electron density map revealed that CD2AP consists of a central coiled-coil domain, which forms the tetramer interface, surrounded by four symmetry-related motifs, each containing three globular domains corresponding to the three SH3 domains. The spatial organization exposes the binding sites of all 12 SH3 domains in the tetramer, allowing simultaneous binding to multiple targets. Determination of the structure of CD2AP provides novel insights into the biology of this slit diaphragm protein and lays the groundwork for characterizing the interactions between key molecules of the slit diaphragm that control glomerular filtration.
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Affiliation(s)
- Brian D Adair
- Department of Medicine, Division of Nephrology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts;
| | - Mehmet M Altintas
- Department of Medicine, Rush University Medical Center, Chicago, Illinois; and
| | - Clemens C Möller
- Department of Medicine, Division of Nephrology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - M Amin Arnaout
- Department of Medicine, Division of Nephrology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; Department of Developmental and Regenerative Biology, Harvard Medical School, Boston, Massachusetts
| | - Jochen Reiser
- Department of Medicine, Rush University Medical Center, Chicago, Illinois; and
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10
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Soekmadji C, Russell PJ, Nelson CC. Exosomes in prostate cancer: putting together the pieces of a puzzle. Cancers (Basel) 2013; 5:1522-44. [PMID: 24351670 PMCID: PMC3875952 DOI: 10.3390/cancers5041522] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 10/21/2013] [Accepted: 11/01/2013] [Indexed: 01/08/2023] Open
Abstract
Exosomes have been shown to act as mediators for cell to cell communication and as a potential source of biomarkers for many diseases, including prostate cancer. Exosomes are nanosized vesicles secreted by cells and consist of proteins normally found in multivesicular bodies, RNA, DNA and lipids. As a potential source of biomarkers, exosomes have attracted considerable attention, as their protein content resembles that of their cells of origin, even though it is noted that the proteins, miRNAs and lipids found in the exosomes are not a reflective stoichiometric sampling of the contents from the parent cells. While the biogenesis of exosomes in dendritic cells and platelets has been extensively characterized, much less is known about the biogenesis of exosomes in cancer cells. An understanding of the processes involved in prostate cancer will help to further elucidate the role of exosomes and other extracellular vesicles in prostate cancer progression and metastasis. There are few methodologies available for general isolation of exosomes, however validation of those methodologies is necessary to study the role of exosomal-derived biomarkers in various diseases. In this review, we discuss “exosomes” as a member of the family of extracellular vesicles and their potential to provide candidate biomarkers for prostate cancer.
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Affiliation(s)
- Carolina Soekmadji
- Australian Prostate Cancer Research Centre-Queensland, Institute of Health and Biomedical Innovation, Queensland University of Technology, Translational Research Institute, Level 3 West, 37 Kent Street, Brisbane, Queensland 4102, Australia.
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Gururaj AE, Gibson L, Panchabhai S, Bai M, Manyam G, Lu Y, Latha K, Rojas ML, Hwang Y, Liang S, Bogler O. Access to the nucleus and functional association with c-Myc is required for the full oncogenic potential of ΔEGFR/EGFRvIII. J Biol Chem 2012; 288:3428-38. [PMID: 23250739 DOI: 10.1074/jbc.m112.399352] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
ΔEGFR is a potent glioblastoma oncogene which has been studied primarily as a plasma membrane kinase. Using intracranial xenograft studies in mice, we show that blocking ΔEGFR access to the nucleus attenuates its tumorigenicity and, conversely, that promoting nuclear accumulation enhances this, providing the first in vivo evidence that the nuclear actions of ΔEGFR contribute strongly to its oncogenic function. Nuclear actions of ΔEGFR include regulation of gene expression by participation in chromatin-bound complexes, and genome-wide mapping of these sequences by chromatin immunoprecipitation and massively parallel sequencing identified 2294 peaks. Bioinformatic analysis showed enrichment of the E-box motif in the dataset, and c-Myc and ΔEGFR were corecruited to the promoters of and transcriptionally activated a subset of nuclear ΔEGFR chromatin targets. Knockdown of c-Myc decreased the expression of these targets and diminished ΔEGFR-stimulated anchorage-independent colony formation. We conclude that transcriptional regulation of target genes by association with gene regulatory chromatin in cooperation with c-Myc by nuclear ΔEGFR makes a unique contribution to its oncogenicity and propose that this venue provides new targets for therapeutic intervention.
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Affiliation(s)
- Anupama E Gururaj
- Department of Neurosurgery, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA.
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12
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Ihara Y, Morishima-Kawashima M, Nixon R. The ubiquitin-proteasome system and the autophagic-lysosomal system in Alzheimer disease. Cold Spring Harb Perspect Med 2012; 2:a006361. [PMID: 22908190 PMCID: PMC3405832 DOI: 10.1101/cshperspect.a006361] [Citation(s) in RCA: 125] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
As neurons age, their survival depends on eliminating a growing burden of damaged, potentially toxic proteins and organelles-a capability that declines owing to aging and disease factors. Here, we review the two proteolytic systems principally responsible for protein quality control in neurons and their important contributions to Alzheimer disease pathogenesis. In the first section, the discovery of paired helical filament ubiquitination is described as a backdrop for discussing the importance of the ubiquitin-proteasome system in Alzheimer disease. In the second section, we review the prominent involvement of the lysosomal system beginning with pathological endosomal-lysosomal activation and signaling at the very earliest stages of Alzheimer disease followed by the progressive failure of autophagy. These abnormalities, which result in part from Alzheimer-related genes acting directly on these lysosomal pathways, contribute to the development of each of the Alzheimer neuropathological hallmarks and represent a promising therapeutic target.
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Affiliation(s)
- Yasuo Ihara
- Department of Neuropathology, Faculty of Life and Medical Science, Doshisha University, Kyoto, Japan.
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13
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Samoylenko A, Vynnytska-Myronovska B, Byts N, Kozlova N, Basaraba O, Pasichnyk G, Palyvoda K, Bobak Y, Barska M, Mayevska O, Rzhepetsky Y, Shuvayeva H, Lyzogubov V, Usenko V, Savran V, Volodko N, Buchman V, Kietzmann T, Drobot L. Increased levels of the HER1 adaptor protein Rukl/CIN85 contribute to breast cancer malignancy. Carcinogenesis 2012; 33:1976-84. [PMID: 22791810 DOI: 10.1093/carcin/bgs228] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The adaptor protein regulator for ubiquitous kinase/c-Cbl-interacting protein of 85kDa (Ruk/CIN85) was found to modulate HER1/EGFR signaling and processes like cell adhesion and apoptosis. Although these features imply a role in carcinogenesis, it is so far unknown how and by which molecular mechanisms Ruk/CIN85 could affect a certain tumor phenotype. By analyzing samples from breast cancer patients, we found high levels of Ruk(l)/CIN85 especially in lymph node metastases from patients with invasive breast adenocarcinomas, suggesting that Ruk(l)/CIN85 contributes to malignancy. Expression of Ruk(l)/CIN85 in weakly invasive breast adenocarcinoma cells deficient of Ruk(l)/CIN85 indeed converted them into more malignant cells. In particular, Ruk(l)/CIN85 reduced the growth rate, decreased cell adhesion, enhanced anchorage-independent growth, increased motility in both transwell migration and wound healing assays as well as affected the response to epidermal growth factor. Thereby, Ruk(l)/CIN85 led to a more rapid and prolonged epidermal growth factor-dependent activation of Src, Akt and ERK1/2 and treatment with the Src inhibitor PP2 and the PI3K inhibitor LY294002 abolished the Ruk(l)/CIN85-dependent changes in cell motility. Together, this study indicates that high levels of Ruk(l)/CIN85 contribute to the conversion of breast adenocarcinoma cells into a more malignant phenotype via modulation of the Src/Akt pathway.
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Affiliation(s)
- Anatoliy Samoylenko
- Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Ukraine
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14
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Büchse T, Horras N, Lenfert E, Krystal G, Körbel S, Schümann M, Krause E, Mikkat S, Tiedge M. CIN85 interacting proteins in B cells-specific role for SHIP-1. Mol Cell Proteomics 2011; 10:M110.006239. [PMID: 21725061 DOI: 10.1074/mcp.m110.006239] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The Cbl-interacting 85-kDa protein (CIN85) plays an important role as a negative regulator of signaling pathways induced by receptor tyrosine kinases. By assembling multiprotein complexes this versatile adaptor enhances receptor tyrosine kinase-activated clathrin-mediated endocytosis and reduces phosphatidylinositol-3-kinase-induced phosphatidylinositol-3,4,5-trisphosphate production. Here we report the expression of CIN85 in primary splenic B lymphocytes and the B-lymphoma cell lines WEHI 231 and Ba/F3. Cross-linking of the B cell antigen receptor resulted in an increased association of CIN85 with the ubiquitin ligase Cbl. Through a systematic pull-down proteomics approach we identified 51 proteins that interact with CIN85 in B cells, including proteins not shown previously to be CIN85-associated. Among these proteins, the SH2-containing inositol phosphatase 1 (SHIP-1) co-precipitated with both the full-length CIN85 and each of its three SH3 domains. We also showed that this association is constitutive and depends on a region of 79 amino acids near the carboxyl terminus of SHIP-1, a region rich in potential SH3 domain binding sites. Because SHIP-1 is a major negative regulator of the phosphatidylinositol-3-kinase pathway in lymphocytes, we hypothesize that the interaction between SHIP-1 and CIN85 might synergistically facilitate the down-regulation of phosphatidylinositol-3,4,5-trisphosphate levels.
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Affiliation(s)
- Tom Büchse
- Institute of Medical Biochemistry and Molecular Biology, Medical Faculty, University of Rostock, Schillingallee 70, 18057 Rostock, Germany.
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15
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Ren X, Hurley JH. Proline-rich regions and motifs in trafficking: from ESCRT interaction to viral exploitation. Traffic 2011; 12:1282-90. [PMID: 21518163 DOI: 10.1111/j.1600-0854.2011.01208.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Most membrane-enveloped viruses bud from infected cells by hijacking the host ESCRT machinery. The ESCRTs are recruited to the budding sites by viral proteins that contain short proline (Pro)-rich motifs (PRMs) known as late domains. The late domains probably evolved by co-opting host PRMs involved in the normal functions of ESCRTs in endosomal sorting and cytokinesis. The solution and crystal structures of PRMs bound to their interaction partners explain the conserved roles of Pro and other residues that predominate in these sequences. PRMs are often grouped together in much larger Pro-rich regions (PRRs) of as many as 150 residues. The PRR of the ESCRT-associated protein, ALIX, autoregulates its conformation and activity. The robustness of different viral budding and host pathways to impairments in Pro-based interactions varies considerably. The known biology of PRM recognition in the ESCRT pathway seems, in principle, compatible with antiviral development, given our increasingly nuanced understanding of the relative weakness and robustness of the host and viral processes.
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Affiliation(s)
- Xuefeng Ren
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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16
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Chumbalkar V, Latha K, Hwang Y, Maywald R, Hawley L, Sawaya R, Diao L, Baggerly K, Cavenee WK, Furnari FB, Bogler O. Analysis of phosphotyrosine signaling in glioblastoma identifies STAT5 as a novel downstream target of ΔEGFR. J Proteome Res 2011; 10:1343-52. [PMID: 21214269 DOI: 10.1021/pr101075e] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
An in-frame deletion mutation in Epidermal Growth Receptor (EGFR), ΔEGFR is a common and potent oncogene in glioblastoma (GBM), promoting growth and survival of cancer cells. This mutated receptor is ligand independent and constitutively active. Its activity is low in intensity and thought to be qualitatively different from acutely ligand stimulated wild-type receptor implying that the preferred downstream targets of ΔEGFR play a significant role in malignancy. To understand the ΔEGFR signal, we compared it to that of a kinase-inactivated mutant of ΔEGFR and wild-type EGFR with shotgun phosphoproteomics using an electron-transfer dissociation (ETD) enabled ion trap mass spectrometer. We identified and quantified 354 phosphopeptides corresponding to 249 proteins. Among the ΔEGFR-associated phosphorylations were the previously described Gab1, c-Met and Mig-6, and also novel phosphorylations including that of STAT5 on Y694/9. We have confirmed the most prominent phosphorylation events in cultured cells and in murine xenograft models of glioblastoma. Pathway analysis of these proteins suggests a preference for an alternative signal transduction pathway by ΔEGFR compared to wild-type EGFR. This understanding will potentially benefit the search for new therapeutic targets for ΔEGFR expressing tumors.
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Affiliation(s)
- Vaibhav Chumbalkar
- Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
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17
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Conserved genes act as modifiers of invertebrate SMN loss of function defects. PLoS Genet 2010; 6:e1001172. [PMID: 21124729 PMCID: PMC2965752 DOI: 10.1371/journal.pgen.1001172] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Accepted: 09/21/2010] [Indexed: 01/27/2023] Open
Abstract
Spinal Muscular Atrophy (SMA) is caused by diminished function of the Survival of Motor Neuron (SMN) protein, but the molecular pathways critical for SMA pathology remain elusive. We have used genetic approaches in invertebrate models to identify conserved SMN loss of function modifier genes. Drosophila melanogaster and Caenorhabditis elegans each have a single gene encoding a protein orthologous to human SMN; diminished function of these invertebrate genes causes lethality and neuromuscular defects. To find genes that modulate SMN function defects across species, two approaches were used. First, a genome-wide RNAi screen for C. elegans SMN modifier genes was undertaken, yielding four genes. Second, we tested the conservation of modifier gene function across species; genes identified in one invertebrate model were tested for function in the other invertebrate model. Drosophila orthologs of two genes, which were identified originally in C. elegans, modified Drosophila SMN loss of function defects. C. elegans orthologs of twelve genes, which were originally identified in a previous Drosophila screen, modified C. elegans SMN loss of function defects. Bioinformatic analysis of the conserved, cross-species, modifier genes suggests that conserved cellular pathways, specifically endocytosis and mRNA regulation, act as critical genetic modifiers of SMN loss of function defects across species.
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Sangsuriya P, Rojtinnakorn J, Senapin S, Flegel TW. Identification and characterization of Alix/AIP1 interacting proteins from the black tiger shrimp, Penaeus monodon. JOURNAL OF FISH DISEASES 2010; 33:571-581. [PMID: 20412359 DOI: 10.1111/j.1365-2761.2010.01156.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Apoptosis is proposed to be a major cause of death in shrimp viral infections. From our previous study, an apoptosis-related gene, Pm-Alix, was identified from the black tiger shrimp. Its expression was high in defence-related tissues including haemocytes and the lymphoid organ. To clarify its possible role in shrimp, we used Pm-Alix as bait in a yeast two-hybrid analysis to search for Alix interacting proteins in shrimp. Two cDNA sequences discovered had homology to a predicted ubiquitin C of the purple sea urchin, Strongylocentrotus purpuratus, and to a guanylyl cyclase of the red swamp crayfish, Procambarus clarkii. In vitro pull-down assays confirmed positive interaction between Pm-Alix and both proteins. Tissue distribution analysis revealed that Pm-Alix and the two binding partners were widely expressed in various tissues but more highly expressed in haemocytes. However, no significant positive or negative correlation was found in the expression of these genes as shrimp approached morbidity and death after challenge with white spot syndrome virus. Thus, the results suggested that Alix and its interacting partners did not play a direct role related to shrimp death.
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Affiliation(s)
- P Sangsuriya
- Centex Shrimp, Faculty of Science, Mahidol University, Bangkok, Thailand
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19
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Shimokawa N, Haglund K, Hölter SM, Grabbe C, Kirkin V, Koibuchi N, Schultz C, Rozman J, Hoeller D, Qiu CH, Londoño MB, Ikezawa J, Jedlicka P, Stein B, Schwarzacher SW, Wolfer DP, Ehrhardt N, Heuchel R, Nezis I, Brech A, Schmidt MHH, Fuchs H, Gailus-Durner V, Klingenspor M, Bogler O, Wurst W, Deller T, de Angelis MH, Dikic I. CIN85 regulates dopamine receptor endocytosis and governs behaviour in mice. EMBO J 2010; 29:2421-32. [PMID: 20551902 DOI: 10.1038/emboj.2010.120] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2009] [Accepted: 05/17/2010] [Indexed: 01/17/2023] Open
Abstract
Despite extensive investigations of Cbl-interacting protein of 85 kDa (CIN85) in receptor trafficking and cytoskeletal dynamics, little is known about its functions in vivo. Here, we report the study of a mouse deficient of the two CIN85 isoforms expressed in the central nervous system, exposing a function of CIN85 in dopamine receptor endocytosis. Mice lacking CIN85 exon 2 (CIN85(Deltaex2)) show hyperactivity phenotypes, characterized by increased physical activity and exploratory behaviour. Interestingly, CIN85(Deltaex2) animals display abnormally high levels of dopamine and D2 dopamine receptors (D2DRs) in the striatum, an important centre for the coordination of animal behaviour. Importantly, CIN85 localizes to the post-synaptic compartment of striatal neurons in which it co-clusters with D2DRs. Moreover, it interacts with endocytic regulators such as dynamin and endophilins in the striatum. Absence of striatal CIN85 causes insufficient complex formation of endophilins with D2DRs in the striatum and ultimately decreased D2DR endocytosis in striatal neurons in response to dopamine stimulation. These findings indicate an important function of CIN85 in the regulation of dopamine receptor functions and provide a molecular explanation for the hyperactive behaviour of CIN85(Deltaex2) mice.
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Affiliation(s)
- Noriaki Shimokawa
- Institute of Biochemistry II and Cluster of Excellence Macromolecular Complexes, Goethe University, Frankfurt (Main), Germany
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20
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Giannoni P, Narcisi R, De Totero D, Romussi G, Quarto R, Bisio A. The administration of demethyl fruticulin A from Salvia corrugata to mammalian cells lines induces "anoikis", a special form of apoptosis. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2010; 17:449-456. [PMID: 19682878 DOI: 10.1016/j.phymed.2009.07.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Revised: 06/01/2009] [Accepted: 07/09/2009] [Indexed: 05/28/2023]
Abstract
Recently demethyl fruticulin A was identified as the major diterpenoid component of the exudates produced by the trichomes of Salvia corrugata leafs. Given the documented apoptotic effects of some of the other known components of the exudates from Salvia species, we assessed if demethyl fruticulin A, once administered to mammalian cells, was involved in the onset of apoptosis and if its biological effects were exerted through the participation of a scavenger membrane receptor, CD36. Three model cell lines were chosen, one of which lacking CD36 expression. Functional availability of the receptor, or its transcriptional rate, were blocked/reduced with a specific antibody or by the administration of vitamin E. Immunodetection of cell cytoskeletal components and tunel analysis revealed that demethyl fruticulin A triggers the onset of anoikis, a special form of apoptosis induced by cell detachment from the substrate. Impairment of CD36 availability/transcription confirmed the receptor partial involvement in the intake of the substance and in anoikis, as also sustained by FACS analysis and by the downregulation of p95, a marker of anoikis, upon blockade of CD36 transcription. However, experiments with CD36-deficient cells suggested that alternate pathways, still to be determined, may take part in the biological effects exerted by demethyl fruticulin A.
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Affiliation(s)
- Paolo Giannoni
- Stem Cell Laboratory, Advanced Biotechnology Center, Largo R. Benzi 10, 16132 Genova, Italy.
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21
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Havrylov S, Redowicz MJ, Buchman VL. Emerging roles of Ruk/CIN85 in vesicle-mediated transport, adhesion, migration and malignancy. Traffic 2010; 11:721-31. [PMID: 20331533 DOI: 10.1111/j.1600-0854.2010.01061.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Ruk/CIN85 is an adaptor protein. Similar to many other proteins of this type, Ruk/CIN85 is known to take part in multiple cellular processes including signal transduction, vesicle-mediated transport, cytoskeleton remodelling, programmed cell death and viral infection. Recent studies have also revealed the potential importance of Ruk/CIN85 in cancer cell invasiveness. In this review we summarize the various roles of this protein as well as the potential contribution of Ruk/CIN85 to malignancy and the invasiveness of cancer cells. In the last section of the paper we also speculate on the utility of Ruk/CIN85 as a target for novel anti-cancer therapies.
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Affiliation(s)
- Serhiy Havrylov
- Nencki Institute of Experimental Biology, Pasteura 3 Street, 02-093 Warsaw, Poland
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22
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Chen HY, Fermin A, Vardhana S, Weng IC, Lo KFR, Chang EY, Maverakis E, Yang RY, Hsu DK, Dustin ML, Liu FT. Galectin-3 negatively regulates TCR-mediated CD4+ T-cell activation at the immunological synapse. Proc Natl Acad Sci U S A 2009; 106:14496-501. [PMID: 19706535 PMCID: PMC2732795 DOI: 10.1073/pnas.0903497106] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Indexed: 12/16/2022] Open
Abstract
We have investigated the function of endogenous galectin-3 in T cells. Galectin-3-deficient (gal3(-/-)) CD4(+) T cells secreted more IFN-gamma and IL-4 than gal3(+/+)CD4(+) T cells after T-cell receptor (TCR) engagement. Galectin-3 was recruited to the cytoplasmic side of the immunological synapse (IS) in activated T cells. In T cells stimulated on supported lipid bilayers, galectin-3 was primarily located at the peripheral supramolecular activation cluster (pSMAC). Gal3(+/+) T cells formed central SMAC on lipid bilayers less effectively and adhered to antigen-presenting cells less firmly than gal3(-/-) T cells, suggesting that galectin-3 destabilizes the IS. Galectin-3 expression was associated with lower levels of early signaling events and phosphotyrosine signals at the pSMAC. Additional data suggest that galectin-3 potentiates down-regulation of TCR in T cells. By yeast two-hybrid screening, we identified as a galectin-3-binding partner, Alix, which is known to be involved in protein transport and regulation of cell surface expression of certain receptors. Co-immunoprecipitation confirmed galectin-3-Alix association and immunofluorescence analysis demonstrated the translocation of Alix to the IS in activated T cells. We conclude that galectin-3 is an inhibitory regulator of T-cell activation and functions intracellularly by promoting TCR down-regulation, possibly through modulating Alix's function at the IS.
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Affiliation(s)
- Huan-Yuan Chen
- Department of Dermatology, School of Medicine, University of California at Davis, Sacramento, CA 95817
| | - Agnes Fermin
- Department of Dermatology, School of Medicine, University of California at Davis, Sacramento, CA 95817
| | - Santosh Vardhana
- Helen L. and Martin S. Kimmel Center for Biology and Medicine, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016
| | - I-Chun Weng
- Department of Dermatology, School of Medicine, University of California at Davis, Sacramento, CA 95817
| | - Kin Fong Robin Lo
- Department of Dermatology, School of Medicine, University of California at Davis, Sacramento, CA 95817
| | - En-Yuh Chang
- La Jolla Institute for Allergy and Immunology, San Diego, CA 92037; and
| | - Emanual Maverakis
- Department of Dermatology, School of Medicine, University of California at Davis, Sacramento, CA 95817
- Veterans Affairs Northern California Health Care System, Sacramento, CA 95655
| | - Ri-Yao Yang
- Department of Dermatology, School of Medicine, University of California at Davis, Sacramento, CA 95817
| | - Daniel K Hsu
- Department of Dermatology, School of Medicine, University of California at Davis, Sacramento, CA 95817
| | - Michael L. Dustin
- Helen L. and Martin S. Kimmel Center for Biology and Medicine, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016
| | - Fu-Tong Liu
- Department of Dermatology, School of Medicine, University of California at Davis, Sacramento, CA 95817
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23
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Proteins recruited by SH3 domains of Ruk/CIN85 adaptor identified by LC-MS/MS. Proteome Sci 2009; 7:21. [PMID: 19531213 PMCID: PMC2702278 DOI: 10.1186/1477-5956-7-21] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Accepted: 06/16/2009] [Indexed: 11/27/2022] Open
Abstract
Background Ruk/CIN85 is a mammalian adaptor molecule with three SH3 domains. Using its SH3 domains Ruk/CIN85 can cluster multiple proteins and protein complexes, and, consequently, facilitates organisation of elaborate protein interaction networks with diverse regulatory roles. Previous research linked Ruk/CIN85 with the regulation of vesicle-mediated transport and cancer cell invasiveness. Despite the recent findings, precise molecular functions of Ruk/CIN85 in these processes remain largely elusive and further research is hampered by a lack of complete lists of its partner proteins. Results In the present study we employed a LC-MS/MS-based experimental pipeline to identify a considerable number (over 100) of proteins recruited by the SH3 domains of Ruk/CIN85 in vitro. Most of these identifications are novel Ruk/CIN85 interaction candidates. The identified proteins have diverse molecular architectures and can interact with other proteins, as well as with lipids and nucleic acids. Some of the identified proteins possess enzymatic activities. Functional profiling analyses and literature mining demonstrate that many of the proteins recruited by the SH3 domains of Ruk/CIN85 identified in this work were involved in the regulation of membranes and cytoskeletal structures necessary for vesicle-mediated transport and cancer cell invasiveness. Several groups of the proteins were also associated with few other cellular processes not previously related to Ruk/CIN85, most prominently with cell division. Conclusion Obtained data support the notion that Ruk/CIN85 regulates vesicle-mediated transport and cancer cell invasiveness through the assembly of multimeric protein complexes governing coordinated remodelling of membranes and underlying cytoskeletal structures, and imply its important roles in formation of coated vesicles and biogenesis of invadopodia. In addition, this study points to potential involvement of Ruk/CIN85 in other cellular processes, chiefly in cell division.
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24
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Novel Insights into the Mechanisms of CIN85 SH3 Domains Binding to Cbl Proteins: Solution-Based Investigations and In Vivo Implications. J Mol Biol 2009; 387:1120-36. [DOI: 10.1016/j.jmb.2009.02.061] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 02/20/2009] [Accepted: 02/24/2009] [Indexed: 11/21/2022]
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Abstract
Alix [ALG-2 (apoptosis-linked gene 2)-interacting protein X] is a ubiquitinous adaptor protein first described for its capacity to bind to the calcium-binding protein, ALG-2. Alix regulates neuronal death in ways involving interactions with ALG-2 and with proteins of the ESCRT (endosomal sorting complex required for transport). Even though all Alix interactors characterized to date are involved in endosomal trafficking, the genuine function of the protein in this process remains unclear. We have demonstrated recently that Alix and ALG-2 form in the presence of calcium, a complex with apical caspases and with the endocytosed death receptor TNFR1 (tumour necrosis factor alpha receptor 1), thus suggesting a molecular coupling between endosomes and the cell death machinery.
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26
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Nikolaienko O, Skrypkina I, Tsyba L, Fedyshyn Y, Morderer D, Buchman V, de la Luna S, Drobot L, Rynditch A. Intersectin 1 forms a complex with adaptor protein Ruk/CIN85 in vivo independently of epidermal growth factor stimulation. Cell Signal 2009; 21:753-9. [PMID: 19166927 DOI: 10.1016/j.cellsig.2009.01.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Accepted: 01/03/2009] [Indexed: 10/21/2022]
Abstract
Intersectin 1 (ITSN1) is an adaptor protein involved in clathrin-mediated endocytosis, apoptosis, signal transduction and cytoskeleton organization. Here, we show that ITSN1 forms a complex with adaptor protein Ruk/CIN85, implicated in downregulation of receptor tyrosine kinases. The interaction is mediated by the SH3A domain of ITSN1 and the third or fourth proline-rich blocks of Ruk/CIN85, and does not depend on epidermal growth factor stimulation, suggesting a constitutive association of ITSN1 with Ruk/CIN85. Moreover, both proteins colocalize in MCF-7 cells with their common binding partner, the ubiquitin ligase c-Cbl. The possible biological role of the interaction between ITSN1 and Ruk/CIN85 is discussed.
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Affiliation(s)
- Oleksii Nikolaienko
- Institute of Molecular Biology and Genetics, 150 Zabolotnogo Street, Kyiv 03680, Ukraine
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27
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Mahul-Mellier AL, Strappazzon F, Petiot A, Chatellard-Causse C, Torch S, Blot B, Freeman K, Kuhn L, Garin J, Verna JM, Fraboulet S, Sadoul R. Alix and ALG-2 are involved in tumor necrosis factor receptor 1-induced cell death. J Biol Chem 2008; 283:34954-65. [PMID: 18936101 PMCID: PMC3259881 DOI: 10.1074/jbc.m803140200] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2008] [Revised: 10/01/2008] [Indexed: 12/29/2022] Open
Abstract
Alix/AIP1 regulates cell death in a way involving interactions with the calcium-binding protein ALG-2 and with proteins of ESCRT (endosomal sorting complex required for transport). Using mass spectrometry we identified caspase-8 among proteins co-immunoprecipitating with Alix in dying neurons. We next demonstrated that Alix and ALG-2 interact with pro-caspase-8 and that Alix forms a complex with the TNFalpha receptor-1 (TNF-R1), depending on its capacity to bind ESCRT proteins. Thus, Alix and ALG-2 may allow the recruitment of pro-caspase-8 onto endosomes containing TNF-R1, a step thought to be necessary for activation of the apical caspase. In line with this, expression of Alix deleted of its ALG-2-binding site (AlixDeltaALG-2) significantly reduced TNF-R1-induced cell death, without affecting endocytosis of the receptor. In a more physiological setting, we found that programmed cell death of motoneurons, which can be inhibited by AlixDeltaALG-2, is regulated by TNF-R1. Taken together, these results highlight Alix and ALG-2 as new actors of the TNF-R1 pathway.
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Affiliation(s)
- Anne-Laure Mahul-Mellier
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
| | - Flavie Strappazzon
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
| | - Anne Petiot
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
| | - Christine Chatellard-Causse
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
| | - Sakina Torch
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
| | - Béatrice Blot
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
| | - Kimberley Freeman
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
| | - Loriane Kuhn
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
| | - Jérome Garin
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
| | - Jean-Marc Verna
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
| | - Sandrine Fraboulet
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
| | - Rémy Sadoul
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
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28
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Differential requirements for Alix and ESCRT-III in cytokinesis and HIV-1 release. Proc Natl Acad Sci U S A 2008; 105:10541-6. [PMID: 18641129 DOI: 10.1073/pnas.0802008105] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The ESCRT machinery functions in topologically equivalent membrane fission events, namely multivesicular body formation, the terminal stages of cytokinesis and HIV-1 release. Here, we show that the ESCRT-III-binding protein Alix is recruited to the midbody of dividing cells through binding Cep55 via an evolutionarily conserved peptide. Disruption of Cep55/Alix/ESCRT-III interactions causes formation of aberrant midbodies and cytokinetic failure, demonstrating an essential role for these proteins in midbody morphology and cell division. We also show that the C terminus of Alix encodes a multimerization activity that is essential for its function in Alix-dependent HIV-1 release and for interaction with Tsg101. Last, we demonstrate that overexpression of Chmp4b and Chmp4c differentially inhibits HIV-1 release and cytokinesis, suggesting possible reasons for gene expansion within the mammalian Class E VPS pathway.
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29
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Bian M, Yu M, Yang S, Gao H, Huang Y, Deng C, Gao Y, Sun F, Huang F. Expression of Cbl-interacting protein of 85 kDa in MPTP mouse model of Parkinson's disease and 1-methyl-4-phenyl-pyridinium ion-treated dopaminergic SH-SY5Y cells. Acta Biochim Biophys Sin (Shanghai) 2008; 40:505-12. [PMID: 18535749 DOI: 10.1111/j.1745-7270.2008.00423.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The newly discovered Cbl-interacting protein of 85 kDa (CIN85) is involved in many cellular processes, but its functions in the brain and in neurodegenerative diseases remain unclear. In this paper, we investigated the distribution of CIN85 protein in different regions of adult mouse brain using Western blot analysis and immunohistochemistry, and found that CIN85 was ubiquitously expressed in mouse brain. In the striatum and substantia nigra, two regions most deeply affected in Parkinson's disease, the level of CIN85 protein was relatively high. In the MPTP mouse model of Parkinson's disease, the expression of CIN85 in the striatum and substantia nigra was complicated. But in 1-methyl-4-phenyl-pyridinium ion-treated human dopaminergic SH-SY5Y cells, the expression of CIN85 increased dramatically. Knocking down of CIN85 by short hairpin RNA reduced SH-SY5Y cell death. Therefore, CIN85 might play different roles in the dopaminergic cell line and in the nigrostriatum of mouse brain under neurotoxin challenge.
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Affiliation(s)
- Minjuan Bian
- National Key Laboratory of Medical Neurobiology, Shanghai Medical College, Fudan University, Shanghai 200032, China
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30
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Havrylov S, Ichioka F, Powell K, Borthwick EB, Baranska J, Maki M, Buchman VL. Adaptor Protein Ruk/CIN85 is Associated with a Subset of COPI-Coated Membranes of the Golgi Complex. Traffic 2008; 9:798-812. [DOI: 10.1111/j.1600-0854.2008.00724.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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31
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Johnson RI, Seppa MJ, Cagan RL. The Drosophila CD2AP/CIN85 orthologue Cindr regulates junctions and cytoskeleton dynamics during tissue patterning. ACTA ACUST UNITED AC 2008; 180:1191-204. [PMID: 18362180 PMCID: PMC2290846 DOI: 10.1083/jcb.200706108] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Developing tissues require cells to undergo intricate processes to shift into appropriate niches. This requires a functional connection between adhesion-mediating events at the cell surface and a cytoskeletal reorganization to permit directed movement. A small number of proteins are proposed to link these processes. Here, we identify one candidate, Cindr, the sole Drosophila melanogaster member of the CD2AP/CIN85 family (this family has been previously implicated in a variety of processes). Using D. melanogaster retina, we demonstrate that Cindr links cell surface junctions (E-cadherin) and adhesion (Roughest) with multiple components of the actin cytoskeleton. Reducing cindr activity leads to defects in local cell movement and, consequently, tissue patterning and cell death. Cindr activity is required for normal localization of Drosophila E-cadherin and Roughest, and we show additional physical and functional links to multiple components of the actin cytoskeleton, including the actin-capping proteins capping protein alpha and capping protein beta. Together, these data demonstrate that Cindr is involved in dynamic cell rearrangement in an emerging epithelium.
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Affiliation(s)
- Ruth I Johnson
- Department of Developmental and Regenerative Biology, Mount Sinai Medical School, New York, NY 10029, USA
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32
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Ichioka F, Kobayashi R, Katoh K, Shibata H, Maki M. Brox, a novel farnesylated Bro1 domain-containing protein that associates with charged multivesicular body protein 4 (CHMP4). FEBS J 2008; 275:682-92. [PMID: 18190528 DOI: 10.1111/j.1742-4658.2007.06230.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Human Brox is a newly identified 46 kDa protein that has a Bro1 domain-like sequence and a C-terminal thioester-linkage site of isoprenoid lipid (CAAX motif) (C standing for cysteine, A for generally aliphatic amino acid, and X for any amino acid). Mammalian Alix and its yeast ortholog, Bro1, are known to associate with charged multivesicular body protein 4 (CHMP4), a component of endosomal sorting complex required for transport III, via their Bro1 domains and to play roles in sorting of ubiquitinated cargoes. We investigated whether Brox has an authentic Bro1 domain on the basis of its capacity for interacting with CHMP4s. Both Strep Tactin binding sequence (Strep)-tagged wild-type Brox (Strep-Brox(WT)) and Strep-tagged farnesylation-defective mutant (Cys-->Ser mutation; Strep-Brox(C408S)) pulled down FLAG-tagged CHMP4b that was coexpressed in HEK293 cells. Treatment of cells with a farnesyltransferase inhibitor, FTI-277, caused an electrophoretic mobility shift of Strep-Brox(WT), and the mobility coincided with that of Strep-Brox(C408S). The inhibitor also caused a mobility shift of endogenous Brox detected by western blotting using polyclonal antibodies to Brox, suggesting farnesylation of Brox in vivo. Fluorescence microscopic analyses revealed that Strep-Brox(WT) exhibited accumulation in the perinuclear area and caused a punctate pattern of FLAG-CHMP4b that was constitutively expressed in HEK293 cells. On the other hand, Strep-Brox(C408S) showed a diffuse pattern throughout the cell, including the nucleus, and did not cause accumulation of FLAG-CHMP4b. Fluorescent signals of monomeric green fluorescent protein (mGFP)-fused Brox(WT) merged partly with those of Golgi markers and with those of abnormal endosomes induced by overexpression of a dominant negative mutant of AAA type ATPase SKD1/Vps4B in HeLa cells, but such colocalization was less efficient for mGFP-Brox(C408S). These results suggest a physiological significance of farnesylation of Brox in its subcellular distribution and efficient interaction with CHMP4s in vivo.
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Affiliation(s)
- Fumitaka Ichioka
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Japan
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33
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Structural and functional studies of ALIX interactions with YPX(n)L late domains of HIV-1 and EIAV. Nat Struct Mol Biol 2007; 15:43-9. [PMID: 18066081 DOI: 10.1038/nsmb1319] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Accepted: 09/21/2007] [Indexed: 12/21/2022]
Abstract
Retrovirus budding requires short peptide motifs (late domains) located within the viral Gag protein that function by recruiting cellular factors. The YPX(n)L late domains of HIV and other lentiviruses recruit the protein ALIX (also known as AIP1), which also functions in vesicle formation at the multivesicular body and in the abscission stage of cytokinesis. Here, we report the crystal structures of ALIX in complex with the YPX(n)L late domains from HIV-1 and EIAV. The two distinct late domains bind at the same site on the ALIX V domain but adopt different conformations that allow them to make equivalent contacts. Binding studies and functional assays verified the importance of key interface residues and revealed that binding affinities are tuned by context-dependent effects. These results reveal how YPX(n)L late domains recruit ALIX to facilitate virus budding and how ALIX can bind YPX(n)L sequences with both n = 1 and n = 3.
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34
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Feng Z, Wu CF, Zhou X, Kuang J. Alternative polyadenylation produces two major transcripts of Alix. Arch Biochem Biophys 2007; 465:328-35. [PMID: 17673164 PMCID: PMC4104816 DOI: 10.1016/j.abb.2007.06.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2007] [Revised: 06/21/2007] [Accepted: 06/21/2007] [Indexed: 01/23/2023]
Abstract
The mammalian adaptor protein Alix participates in multiple cellular processes. Since mouse Alix cDNA detects two distinct transcripts of approximately 3.5 and approximately 7.0 kb in various mouse tissues, it is possible that there exist isoforms of Alix protein that perform varied biological functions. In this study, we first demonstrate that four different anti-Alix monoclonal antibodies immunoblot the single Alix protein in nine different mouse tissues. We then show that the two transcripts of 3.2 and 6.4 kb are widely expressed in various human tissues and cell lines. These two transcripts are generated from the same Alix gene localizing at 3p22.3 via alternative polyadenylation, thus containing an identical open reading frame. However, the 3.2-kb transcript is much more active in translation than the 6.4-kb transcript in a randomly selected cell line. These results eliminate the possibility that the two transcript variants encode different isoforms of Alix protein and suggest that alternative polyadenylation is one of the mechanisms controlling Alix protein expression.
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Affiliation(s)
| | | | - Xi Zhou
- Departments of Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030
| | - Jian Kuang
- Departments of Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030
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35
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Laifenfeld D, Patzek LJ, McPhie DL, Chen Y, Levites Y, Cataldo AM, Neve RL. Rab5 mediates an amyloid precursor protein signaling pathway that leads to apoptosis. J Neurosci 2007; 27:7141-53. [PMID: 17611268 PMCID: PMC6794581 DOI: 10.1523/jneurosci.4599-06.2007] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Alzheimer's disease (AD) involves activation of apoptotic pathways that may be regulated through signaling cascades initiated by the amyloid precursor protein (APP). Enlarged endosomes have been observed in postmortem AD brains at very early stages of the disease. We show here that exogenous expression of a familial AD (FAD) mutant of APP or of the APP binding protein APP-BP1 in neurons causes enlargement of early endosomes, increased receptor-mediated endocytosis via a pathway dependent on APP-BP1 binding to APP, and apoptosis. Levels of both APP-BP1 and Rab5 are elevated in early endosomes in cortical embryonic neurons expressing APP(V642I) or APP-BP1, in cultured skin fibroblast cells from Down syndrome subjects, and in postmortem hippocampal tissue of individuals with AD. Indeed, Rab5 was found to bind specifically to APP-BP1, between amino acids 443 and 479. Inhibition of Rab5 or dynamin activity, but not of Eps15 (epidermal growth factor receptor pathway substrate 15) activity, rescued neurons from apoptosis induced by either APP(V642I) or APP-BP1, without affecting levels of intracellular or secreted amyloid-beta (Abeta). Induction of Rab5 activity via expression of a constitutively active mutant led to an increase in neuronal apoptosis more than twice that attributable to induction of endosome enlargement via a Rab5-independent mechanism, regardless of Abeta production. Together, these findings suggest that Rab5 activation via an APP/APP-BP1-initiated signaling pathway mediates neuronal apoptosis caused by FAD mutants of APP and that, within this pathway, Rab5 has a specific role in signaling that is distinct from, although not independent of, its role in trafficking.
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Affiliation(s)
- Daphna Laifenfeld
- Department of Psychiatry, Harvard Medical School, McLean Hospital, Belmont, Massachusetts 02478
| | - Lucas J. Patzek
- Department of Psychiatry, Harvard Medical School, McLean Hospital, Belmont, Massachusetts 02478
| | - Donna L. McPhie
- Department of Psychiatry, Harvard Medical School, McLean Hospital, Belmont, Massachusetts 02478
| | - Yuzhi Chen
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, and
| | - Yona Levites
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida 32224
| | - Anne M. Cataldo
- Department of Psychiatry, Harvard Medical School, McLean Hospital, Belmont, Massachusetts 02478
| | - Rachael L. Neve
- Department of Psychiatry, Harvard Medical School, McLean Hospital, Belmont, Massachusetts 02478
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36
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Gaidos G, Soni S, Oswald DJ, Toselli PA, Kirsch KH. Structure and function analysis of the CMS/CIN85 protein family identifies actin-bundling properties and heterotypic-complex formation. J Cell Sci 2007; 120:2366-77. [PMID: 17606992 DOI: 10.1242/jcs.004333] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Members of the CMS/CIN85 protein family participate in clathrin-mediated endocytosis and play a crucial role in maintaining the kidney filtration barrier. The CMS protein structure includes three Src homology 3 (SH3) domains and a proline-rich (PR) region that is connected by a `linker' sequence to a coiled-coil (CC) domain. We show that CMS is a component of special actin-rich adhesion structures – podosomes – and demonstrate specific actin-binding properties of CMS. We have found that the entire C-terminal half of CMS is necessary for efficient binding to filamentous actin (F-actin). CMS and CIN85 can crosslink F-actin into bundles, a function that depends on the PR region and the CC domain. Removal of these domains reduces migration. CMS can also form heterotypic complexes with CIN85. CIN85 is expressed as multiple isoforms that share the CC domain, suggesting that heterotypic interactions with CMS provides a mechanism to regulate CMS binding to F-actin and thus for modulating dynamic rearrangements of the cytoskeleton.
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Affiliation(s)
- Gabriel Gaidos
- Department of Biochemistry, Boston University School of Medicine, 715 Albany Street, Boston, MA 02118, USA
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37
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Mattei S, Klein G, Satre M, Aubry L. Trafficking and developmental signaling: Alix at the crossroads. Eur J Cell Biol 2007; 85:925-36. [PMID: 16766083 DOI: 10.1016/j.ejcb.2006.04.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Alix is a phylogenetically conserved protein that participates in mammals in programmed cell death in association with ALG-2, a penta-EF-hand calciprotein. It contains an N-terminal Bro1 domain, a coiled-coil region and a C-terminal proline-rich domain containing several SH3- and WW-binding sites that contribute to its scaffolding properties. Recent data showed that by virtue of its Bro1 domain, Alix is functionally associated to the ESCRT complexes involved in the biogenesis of the multivesicular body and sorting of transmembrane proteins within this specific endosomal compartment. In Dictyostelium, an alx null strain shows a markedly perturbed starvation-induced morphogenetic program while ALG-2 disruptants remain unaffected. This review summarizes Dictyostelium data on Alix and ALG-2 homologues and evaluates whether known functions of Alix in other organisms can account for the developmental arrest of the alx null mutant and how Dictyostelium studies can substantiate the current understanding of the function(s) of this versatile and conserved signaling molecule.
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Affiliation(s)
- Sara Mattei
- Laboratoire de Biochimie et Biophysique des Systemes Integres, DRDC/BBSI, UMR 5092 CNRS-CEA-UJF, CEA-Grenoble, 17 Rue des Martyrs, F-38054 Grenoble cedex 9, France
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38
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Abstract
Alix is a cytosolic protein in mammalian cells that was originally identified on the basis of its association with pro-apoptotic signaling. More recent evidence has established that Alix has a hand in regulating other cellular mechanisms, including endocytic membrane trafficking and cell adhesion. Although Alix appears to participate directly in these various activities, the role it plays in each process has largely been inferred from the functions of proteins with which it interacts. For example, recruitment of Alix to endosomes is mediated by its N-terminal Bro1 domain, the structure of which was recently solved for its yeast orthologue, Bro1. The diversity of Alix functions is due to its proline-rich C-terminus, which provides multiple protein-binding sites. With this blueprint in hand, we can now ask whether Alix acts simply as an adaptor that links different proteins into networks or, instead, contributes a specific function to distinct molecular machineries.
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Affiliation(s)
- Greg Odorizzi
- Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA.
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39
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Gauthier NC, Monzo P, Gonzalez T, Doye A, Oldani A, Gounon P, Ricci V, Cormont M, Boquet P. Early endosomes associated with dynamic F-actin structures are required for late trafficking of H. pylori VacA toxin. ACTA ACUST UNITED AC 2007; 177:343-54. [PMID: 17438076 PMCID: PMC2064141 DOI: 10.1083/jcb.200609061] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Glycosylphosphatidylinositol-anchored proteins (GPI-APs) are endocytosed by a clathrin- independent pathway into vesicles named GPI-AP–enriched early endosomal compartments (GEECs). We recently showed that the vacuolating toxin VacA secreted by Helicobacter pylori is endocytosed into the GEECs (Gauthier, N.C., P. Monzo, V. Kaddai, A. Doye, V. Ricci, and P. Boquet. 2005. Mol. Biol. Cell. 16:4852–4866). Unlike GPI-APs that are mostly recycled back to the plasma membrane, VacA reaches early endosomes (EEs) and then late endosomes (LEs), where vacuolation occurs. In this study, we used VacA to study the trafficking pathway between GEECs and LEs. We found that VacA routing from GEECs to LEs required polymerized actin. During this trafficking, VacA was transferred from GEECs to EEs associated with polymerized actin structures. The CD2-associated protein (CD2AP), a docking protein implicated in intracellular trafficking, bridged the filamentous actin (F-actin) structures with EEs containing VacA. CD2AP regulated those F-actin structures and was required to transfer VacA from GEECs to LEs. These results demonstrate that sorting from GEECs to LEs requires dynamic F-actin structures on EEs.
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Affiliation(s)
- Nils C Gauthier
- Unité 627 and 2Unité 568, Institut National de la Santé et de la Recherche Medicale, Faculty of Medicine, 06107 Nice, Cedex 02, France
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40
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Usami Y, Popov S, Göttlinger HG. Potent rescue of human immunodeficiency virus type 1 late domain mutants by ALIX/AIP1 depends on its CHMP4 binding site. J Virol 2007; 81:6614-22. [PMID: 17428861 PMCID: PMC1900090 DOI: 10.1128/jvi.00314-07] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The release of human immunodeficiency virus type 1 (HIV-1) and of other retroviruses from certain cells requires the presence of distinct regions in Gag that have been termed late assembly (L) domains. HIV-1 harbors a PTAP-type L domain in the p6 region of Gag that engages an endosomal budding machinery through Tsg101. In addition, an auxiliary L domain near the C terminus of p6 binds to ALIX/AIP1, which functions in the same endosomal sorting pathway as Tsg101. In the present study, we show that the profound release defect of HIV-1 L domain mutants can be completely rescued by increasing the cellular expression levels of ALIX and that this rescue depends on an intact ALIX binding site in p6. Furthermore, the ability of ALIX to rescue viral budding in this system depended on two putative surface-exposed hydrophobic patches on its N-terminal Bro1 domain. One of these patches mediates the interaction between ALIX and the ESCRT-III component CHMP4B, and mutations which disrupt the interaction also abolish the activity of ALIX in viral budding. The ability of ALIX to rescue a PTAP mutant also depends on its C-terminal proline-rich domain (PRD), but not on the binding sites for Tsg101, endophilin, CIN85, or for the newly identified binding partner, CMS, within the PRD. Our data establish that ALIX can have a dramatic effect on HIV-1 release and suggest that the ability to use ALIX may allow HIV-1 to replicate in cells that express only low levels of Tsg101.
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Affiliation(s)
- Yoshiko Usami
- Program in Gene Function and Expression, University of Massachusetts Medical School, LRB 526, 364 Plantation Street, Worcester, MA 01605, USA
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41
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Lee S, Joshi A, Nagashima K, Freed EO, Hurley JH. Structural basis for viral late-domain binding to Alix. Nat Struct Mol Biol 2007; 14:194-9. [PMID: 17277784 PMCID: PMC2377018 DOI: 10.1038/nsmb1203] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2006] [Accepted: 01/17/2007] [Indexed: 12/21/2022]
Abstract
The modular protein Alix is a central node in endosomal-lysosomal trafficking and the budding of human immunodeficiency virus (HIV)-1. The Gag p6 protein of HIV-1 contains a LYPx(n)LxxL motif that is required for Alix-mediated budding and binds a region of Alix spanning residues 360-702. The structure of this fragment of Alix has the shape of the letter 'V' and is termed the V domain. The V domain has a topologically complex arrangement of 11 alpha-helices, with connecting loops that cross three times between the two arms of the V. The conserved residue Phe676 is at the center of a large hydrophobic pocket and is crucial for binding to a peptide model of HIV-1 p6. Overexpression of the V domain inhibits HIV-1 release from cells. This inhibition of release is reversed by mutations that block binding of the Alix V domain to p6.
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Affiliation(s)
- Sangho Lee
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (NIH), US Department of Health and Human Services, Bethesda, Maryland 20892, USA
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42
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Liu JP, Liu NS, Yuan HY, Guo Q, Lu H, Li YY. Human homologue of SETA binding protein 1 interacts with cathepsin B and participates in TNF-Induced apoptosis in ovarian cancer cells. Mol Cell Biochem 2007; 292:189-95. [PMID: 16733801 DOI: 10.1007/s11010-006-9214-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Lysosomal cysteine protease cathepsin B has been reported to play an important role in apoptosis of many different cancer cells, but the regulation of cathepsin B in apoptosis is poorly understood. Human homologue of SETA binding protein 1 (hSB1) was identified to interact with cathepsin B by yeast-two hybrid method, and the interaction was confirmed in vitro GST pull-down assay and in vivo coimmunoprecipitation experiment. hSB1 was co-localized with cathepsin B in cellular lysosomes. Our previous study has shown that TNF can induce ovarian cancer cells OV-90 apoptosis and the apoptosis process is cathepsin B-depended. Here we provide evidence that overexpression of cathepsin B-interacting protein hSB1 could suppress TNF-triggered apoptosis in OV-90 cells, but has no effect on cellular cathepsin B activity. hSB1 may function as a regulator of cathepsin B-mediated apoptosis.
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Affiliation(s)
- Jian-Ping Liu
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433, PR China
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DeJournett R, Kobayashi R, Pan S, Wu C, Etkin L, Clark R, Bögler O, Kuang J. Phosphorylation of the proline-rich domain of Xp95 modulates Xp95 interaction with partner proteins. Biochem J 2007; 401:521-31. [PMID: 16978157 PMCID: PMC1820820 DOI: 10.1042/bj20061287] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The mammalian adaptor protein Alix [ALG-2 (apoptosis-linked-gene-2 product)-interacting protein X] belongs to a conserved family of proteins that have in common an N-terminal Bro1 domain and a C-terminal PRD (proline-rich domain), both of which mediate partner protein interactions. Following our previous finding that Xp95, the Xenopus orthologue of Alix, undergoes a phosphorylation-dependent gel mobility shift during progesteroneinduced oocyte meiotic maturation, we explored potential regulation of Xp95/Alix by protein phosphorylation in hormone-induced cell cycle re-entry or M-phase induction. By MALDI-TOF (matrix-assisted laser-desorption ionization-time-of-flight) MS analyses and gel mobility-shift assays, Xp95 is phosphorylated at multiple sites within the N-terminal half of the PRD during Xenopus oocyte maturation, and a similar region in Alix is phosphorylated in mitotically arrested but not serum-stimulated mammalian cells. By tandem MS, Thr745 within this region, which localizes in a conserved binding site to the adaptor protein SETA [SH3 (Src homology 3) domain-containing, expressed in tumorigenic astrocytes] CIN85 (a-cyano-4-hydroxycinnamate)/SH3KBP1 (SH3-domain kinase-binding protein 1), is one of the phosphorylation sites in Xp95. Results from GST (glutathione S-transferase)-pull down and peptide binding/competition assays further demonstrate that the Thr745 phosphorylation inhibits Xp95 interaction with the second SH3 domain of SETA. However, immunoprecipitates of Xp95 from extracts of M-phase-arrested mature oocytes contained additional partner proteins as compared with immunoprecipitates from extracts of G2-arrested immature oocytes. The deubiquitinase AMSH (associated molecule with the SH3 domain of signal transducing adaptor molecule) specifically interacts with phosphorylated Xp95 in M-phase cell lysates. These findings establish that Xp95/Alix is phosphorylated within the PRD during M-phase induction, and indicate that the phosphorylation may both positively and negatively modulate their interaction with partner proteins.
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Affiliation(s)
- Robert E. DeJournett
- *Department of Experimental Therapeutics, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Blvd, Box 019, Houston, TX 77030, U.S.A
- †Department of Neurosurgery and Neuro-Oncology, The University of Texas, M.D. Anderson Cancer Center, 1515 Holcombe Blvd, Box 019, Houston, TX 77030, U.S.A
- ‡Program in Genes and Development, University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030, U.S.A
| | - Ryuji Kobayashi
- §Department of Molecular Pathology, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Blvd, Box 019, Houston, TX 77030, U.S.A
| | - Shujuan Pan
- *Department of Experimental Therapeutics, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Blvd, Box 019, Houston, TX 77030, U.S.A
- †Department of Neurosurgery and Neuro-Oncology, The University of Texas, M.D. Anderson Cancer Center, 1515 Holcombe Blvd, Box 019, Houston, TX 77030, U.S.A
- ‡Program in Genes and Development, University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030, U.S.A
| | - Chuanfen Wu
- ∥Department of Molecular Genetics, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Blvd, Box 019, Houston, TX 77030, U.S.A
| | - Laurence D. Etkin
- ∥Department of Molecular Genetics, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Blvd, Box 019, Houston, TX 77030, U.S.A
| | - Richard B. Clark
- ¶Department of Integrative Biology and Pharmacology, The University of Texas Medical School, Houston, TX 77225, U.S.A
| | - Oliver Bögler
- †Department of Neurosurgery and Neuro-Oncology, The University of Texas, M.D. Anderson Cancer Center, 1515 Holcombe Blvd, Box 019, Houston, TX 77030, U.S.A
- ‡Program in Genes and Development, University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030, U.S.A
| | - Jian Kuang
- *Department of Experimental Therapeutics, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Blvd, Box 019, Houston, TX 77030, U.S.A
- To whom correspondence should be addressed (email )
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Munshi UM, Kim J, Nagashima K, Hurley JH, Freed EO. An Alix fragment potently inhibits HIV-1 budding: characterization of binding to retroviral YPXL late domains. J Biol Chem 2006; 282:3847-55. [PMID: 17158451 DOI: 10.1074/jbc.m607489200] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The retroviral structural protein, Gag, contains small peptide motifs known as late domains that promote efficient virus release from the infected cell. In addition to the well characterized PTAP late domain, the p6 region of HIV-1 Gag contains a binding site for the host cell protein Alix. To better understand the functional role of the Gag/Alix interaction, we overexpressed an Alix fragment composed of residues 364-716 (Alix 364-716) and examined the effect on release of wild type (WT) and Alix binding site mutant HIV-1. We observed that Alix 364-716 expression significantly inhibited WT virus release and Gag processing and that mutation of the Alix binding site largely relieved this inhibition. Furthermore, Alix 364-716 expression induced a severe defect on WT but not mutant particle morphology. Intriguingly, the impact of Alix 364-716 expression on HIV-1 release and Gag processing was markedly different from that induced by mutation of the Alix binding site in p6. The association of Alix 364-716 with HIV-1 and equine infectious anemia virus late domains was quantitatively evaluated by isothermal titration calorimetry and surface plasmon resonance techniques, and the effects of mutations in these viral sequences on Alix 364-716 binding was determined. This study identifies a novel Alix-derived dominant negative inhibitor of HIV-1 release and Gag processing and provides quantitative information on the interaction between Alix and viral late domains.
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Affiliation(s)
- Utpal M Munshi
- Virus-Cell Interaction Section, HIV Drug Resistance Program, National Cancer Institute-Frederick, Frederick, Maryland 21702-1201, USA
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Ichioka F, Takaya E, Suzuki H, Kajigaya S, Buchman VL, Shibata H, Maki M. HD-PTP and Alix share some membrane-traffic related proteins that interact with their Bro1 domains or proline-rich regions. Arch Biochem Biophys 2006; 457:142-9. [PMID: 17174262 DOI: 10.1016/j.abb.2006.11.008] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Revised: 11/07/2006] [Accepted: 11/09/2006] [Indexed: 11/25/2022]
Abstract
Mammalian Alix is a multifunctional adaptor protein involved in cell death, receptor endocytosis, endosomal protein sorting and cell adhesion by associating with various proteins such as ALG-2, CIN85/Rukl/SETA, endophilins, CHMP4s and TSG101. HD-PTP is a paralog of Alix and a putative protein tyrosine phosphatase (PTP) that contains a Bro1 domain, coiled-coils, a proline-rich region (PRR) in addition to a PTP domain. We investigated interactions between HD-PTP and Alix-binding proteins. In the yeast two-hybrid assay, HD-PTP showed positive interactions with CHMP4b/Shax1, TSG101, endophilin A1 and ALG-2 but not with either RabGAPLP or CIN85. We confirmed the interactions in a mammalian system by Strep-pulldown assays in which pulldown products from the lysates of HEK293T cells expressing either Strep-tagged HD-PTP alone or co-expressing with epitope-tagged proteins were analyzed by Western blotting using specific antibodies. While Alix associated with both ALG-2 and TSG101 in a Ca2+-dependent manner, HD-PTP interacted with ALG-2 Ca2+-dependently but with TSG101 Ca2+-independently.
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Affiliation(s)
- Fumitaka Ichioka
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
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Kawata A, Iida J, Ikeda M, Sato Y, Mori H, Kansaku A, Sumita K, Fujiwara N, Rokukawa C, Hamano M, Hirabayashi S, Hata Y. CIN85 is localized at synapses and forms a complex with S-SCAM via dendrin. J Biochem 2006; 139:931-9. [PMID: 16751601 DOI: 10.1093/jb/mvj105] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Membrane-associated guanylate kinase inverted (MAGI)-1 plays a role as a scaffold at cell junctions in non-neuronal cells, while S-SCAM, its neuronal isoform, is involved in the organization of synapses. A search for MAGI-1-interacting proteins by yeast two-hybrid screening of a kidney cDNA library yielded dendrin. As dendrin was originally reported as a brain-specific postsynaptic protein, we tested the interaction between dendrin and S-SCAM and revealed that dendrin binds to the WW domains of S-SCAM. Dendrin is known to be dendritically translated but its function is largely unknown. To gain insights into the physiological meaning of the interaction, we performed a second yeast two-hybrid screening using dendrin as a bait. We identified CIN85, an endocytic scaffold protein, as a putative dendrin-interactor. Immunocytochemistry and subcellular fractionation analysis supported the synaptic localization of CIN85. The first SH3 domain and the C-terminal region of CIN85 bind to the proline-rich region and the N-terminal region of dendrin, respectively. In vitro experiments suggest that dendrin forms a ternary complex with CIN85 and S-SCAM and that this complex formation facilitates the recruitment of dendrin and S-SCAM to vesicle-like structures where CIN85 is accumulated.
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Affiliation(s)
- Akira Kawata
- Department of Medical Biochemistry, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo 113-8519
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Pan S, Wang R, Zhou X, He G, Koomen J, Kobayashi R, Sun L, Corvera J, Gallick GE, Kuang J. Involvement of the conserved adaptor protein Alix in actin cytoskeleton assembly. J Biol Chem 2006; 281:34640-50. [PMID: 16966331 DOI: 10.1074/jbc.m602263200] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The conserved adaptor protein Alix, also called AIP1 or Hp95, promotes flattening and alignment of cultured mammalian fibroblasts; however, the mechanism by which Alix regulates fibroblast morphology is not understood. Here we demonstrate that Alix in WI38 cells, which require Alix expression for maintaining typical fibroblast morphology, associates with filamentous actin (F-actin) and F-actin-based structures lamellipodia and stress fibers. Reducing Alix expression by small interfering RNA (siRNA) decreases F-actin content and inhibits stress fiber assembly. In cell-free systems, Alix directly interacts with F-actin at both the N-terminal Bro1 domain and the C-terminal proline-rich domain. In Alix immunoprecipitates from WI38 cell lysates, actin is the most abundant partner protein of Alix. In addition, the N-terminal half of the middle region of Alix binds cortactin, an activator of the ARP2/3 complex-mediated initiation of actin polymerization. Alix is required for lamellipodial localization of cortactin. The C-terminal half of the middle region of Alix interacts with alpha-actinin, a key factor that bundles F-actin in stress fibers. Alix knockdown decreases the amount of alpha-actinin that associates with F-actin. These findings establish crucial involvement of Alix in actin cytoskeleton assembly.
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Affiliation(s)
- Shujuan Pan
- Department of Experimental Therapeutics, University of Texas, M. D. Anderson Cancer Center, Houston, Texas 77030, USA
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Abstract
The ESCRT complexes and associated proteins comprise a major pathway for the lysosomal degradation of transmembrane proteins and are critical for receptor downregulation, budding of the HIV virus, and other normal and pathological cell processes. The ESCRT system is conserved from yeast to humans. The ESCRT complexes form a network that recruits monoubiquitinated proteins and drives their internalization into lumenal vesicles within a type of endosome known as a multivesicular body. The structures and interactions of many of the components have been determined over the past three years, revealing mechanisms for membrane and cargo recruitment and for complex assembly.
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Affiliation(s)
- James H. Hurley
- Laboratory of Molecular Biology, National Institute of Diabetes
and Digestive and Kidney Diseases, National Institutes of Health, U. S.
Department of Health and Human Services, Bethesda, MD 20892-0580.
| | - Scott D. Emr
- Department of Cellular and Molecular Medicine and Howard Hughes
Medical Institute, University of California at San Diego, 9500 Gilman Dr., La
Jolla, CA 92093-0668.
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Bose R, Molina H, Patterson AS, Bitok JK, Periaswamy B, Bader JS, Pandey A, Cole PA. Phosphoproteomic analysis of Her2/neu signaling and inhibition. Proc Natl Acad Sci U S A 2006; 103:9773-8. [PMID: 16785428 PMCID: PMC1502529 DOI: 10.1073/pnas.0603948103] [Citation(s) in RCA: 166] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Her2/neu (Her2) is a tyrosine kinase belonging to the EGF receptor (EGFR)/ErbB family and is overexpressed in 20-30% of human breast cancers. We sought to characterize Her2 signal transduction pathways further by using MS-based quantitative proteomics. Stably transfected cell lines overexpressing Her2 or empty vector were generated, and the effect of an EGFR and Her2 selective tyrosine kinase inhibitor, PD168393, on these cells was characterized. Quantitative measurements were obtained on 462 proteins by using the SILAC (stable isotope labeling with amino acids in cell culture) method to monitor three conditions simultaneously. Of these proteins, 198 showed a significant increase in tyrosine phosphorylation in Her2-overexpressing cells, and 81 showed a significant decrease in phosphorylation. Treatment of Her2-overexpressing cells with PD168393 showed rapid reversibility of the majority of the Her2-triggered phosphorylation events. Phosphoproteins that were identified included many known Her2 signaling molecules as well as known EGFR signaling proteins that had not been previously linked to Her2, such as Stat1, Dok1, and delta-catenin. Importantly, several previously uncharacterized Her2 signaling proteins were identified, including Axl tyrosine kinase, the adaptor protein Fyb, and the calcium-binding protein Pdcd-6/Alg-2. We also identified a phosphorylation site in Her2, Y877, which is located in the activation loop of the kinase domain, is distinct from the known C-terminal tail autophosphorylation sites, and may have important implications for regulation of Her2 signaling. Network modeling, which combined phosphoproteomic results with literature-curated protein-protein interaction data, was used to suggest roles for some of the previously unidentified Her2 signaling proteins.
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Affiliation(s)
- Ron Bose
- Departments of *Pharmacology
- Oncology, and
| | | | | | | | - Balamurugan Periaswamy
- McKusick–Nathans Institute for Genetic Medicine
- Institute of Bioinformatics, International Tech Park, Bangalore 560066, India
| | - Joel S. Bader
- **Biomedical Engineering
- High-Throughput Biology Center, Johns Hopkins University School of Medicine, Baltimore, MD 21205; and
| | - Akhilesh Pandey
- Oncology, and
- McKusick–Nathans Institute for Genetic Medicine
- To whom correspondence may be addressed. E-mail:
or
| | - Philip A. Cole
- Departments of *Pharmacology
- Oncology, and
- To whom correspondence may be addressed. E-mail:
or
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Tsuda M, Seong KH, Aigaki T. POSH, a scaffold protein for JNK signaling, binds to ALG-2 and ALIX in Drosophila. FEBS Lett 2006; 580:3296-300. [PMID: 16698022 DOI: 10.1016/j.febslet.2006.05.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Revised: 04/28/2006] [Accepted: 05/02/2006] [Indexed: 02/04/2023]
Abstract
Plenty of SH3s (POSH) functions as a scaffold protein for the Jun N-terminal kinase (JNK) signal transduction pathway, which leads to cell death in mammalian cultured cells and Drosophila. Here, we show that POSH forms a complex with Apoptosis-linked gene-2 (ALG-2) and ALG-2-interacting protein (ALIX/AIP1) in a calcium-dependent manner. Overexpression of ALG-2 or ALIX in developing imaginal eye discs resulted in roughened or melanized eyes, respectively. These phenotypes were enhanced by co-overexpression of POSH. We found that overexpression of either gene could induce ectopic JNK activation, suggesting that POSH/ALG-2/ALIX may function together in the regulation of the JNK pathway.
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Affiliation(s)
- Manabu Tsuda
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji-shi, Tokyo 192-0397, Japan
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